Heating device

ABSTRACT

A heating device, including a gas or oil burner in a cylindrical combustion chamber radially bounded by a heat exchanger, at least one gap for the passage of heating gases through the heat exchanger into an exhaust-gas collection chamber, which is radially outside of the heat exchanger and has a surrounding shell having a connection nozzle for an exhaust gas line, a front cover element for accommodating the burner, a rear cover element as a closure for the combustion chamber, and supply/return connection nozzles. The present system is intended to optimize the heat exchanger so as to achieve the most compact possible dimensions and efficient heat transfer properties. The heat exchanger includes annularly configured heat exchanger tubes that are disposed in parallel to the longitudinal axis of combustion chamber, which each form an axially extending gap between two adjacent heat exchanger tubes for passing heating gases in the radial direction.

FIELD OF THE INVENTION

The present invention relates to a heating device, in particular to a condensing heating device.

BACKGROUND INFORMATION

Heating devices of the species are fired by a gas or oil burner and have a cylindrical combustion chamber, the known devices being mostly radially bounded by a helically coiled heat exchanger. The actual heat exchanger surface forms at least one gap between the tubular coils to allow passage of the heating gases. Also customary are a front cover element for accommodating the burner, a rear cover element as a closure for the combustion chamber, supply and return connection nozzles, as well as an exhaust-gas collection chamber that is configured radially outside of the heat exchanger underneath a surrounding shell and is provided with a connection nozzle for an exhaust gas line. With regard to the hot water-side flow guidance, it is a question of a forced-through-flow heat exchanger. A circulating pump provides for a specified water flow rate through the mostly relatively narrow water channels. In this manner, in spite of a low water capacity, fairly high densities are able to be realized for the heat flow entering on the hot gas side.

From the German Utility Model Patent DE 20 2005 011 633 U1, a heating device is discussed having two helically coiled heat exchangers which are screwed into each other and are configured to allow a heating medium to flow therethrough in parallel to one another. In this context, the coil ends, which are configured side-by-side, are joined to one another and have a common connection nozzle. Supply and return connection nozzles are located at opposite end faces of the heat exchanger.

The German Examined Specification DE 10 2004 023 711 B3 likewise discusses a heating device having a helically coiled heat exchanger and at least two hydraulically interconnected coil regions. These are configured to vary in diameter and can be rotated to fit helically into each other. Thus, the exhaust gas first flows through the gap of the inner coil and then continues via an intermediate space through the gap in the outer coil. Since a one-piece tube, in particular a square tube, is also used in this variant, it is hardly possible from a production standpoint to influence the gap geometry.

In addition, a heat exchanger having annular flow channels is discussed in German Patent Application DE 10 2006 029 854 A1. In this case, a plurality of substantially identical annular segments are combined vertically and in parallel to one another to form a heat exchanger. Disposed between the segments is a gap for the passage of the heating gases from the combustion chamber, which is configured in the center, to the outside. This gap is bounded on both sides by the heat transfer surfaces, and the heating medium flows inside of the segments. Even though a forced-through-flow heat exchanger is described, where alternating overflow above and below is provided from segment to segment, problems can arise because a complete venting from the upper regions of the individual segments is not possible.

SUMMARY OF THE INVENTION

It is, therefore, an object of the exemplary embodiments and/or exemplary methods of the present invention to optimize the heat exchanger of a heating device, in particular of a condensing heating device, particularly with respect to achieving the most compact possible dimensions and efficient heat transfer properties.

This is achieved in accordance with the exemplary embodiments and/or exemplary methods of the present invention by the features described herein. Advantageous embodiments may be inferred from the further descriptions herein.

The heating device composed of a cylindrical combustion chamber and a heat exchanger radially bounding the same is characterized in that the heat exchanger is composed of a plurality of annularly configured heat exchanger tubes that are disposed in parallel to the longitudinal axis of the combustion chamber. In each case, an axially extending gap of which may be only 0.5 mm to 2 mm width is formed between two adjacent heat exchanger tubes to allow passage of the heating gases in the radial direction.

The cross section of the heat exchanger tubes is round or oval, or it is flattened to enlarge the gap length in the radial direction. The heat exchanger tubes may also have a box-shaped and/or trapezoidal cross section, in order to provide an especially large heat transfer surface in the gap region.

In a first specific embodiment, the heat exchanger tubes are traversed by flow on the water side, in parallel, from one end face to the other. In this context, the return connection nozzle is installed in the one cover element, and the supply connection nozzle in the other. Thus, the heating medium is uniformly distributed in the cover elements to all channels in the heat exchanger tubes, respectively collected at the outlet thereof.

In a second specific embodiment, all heat exchanger tubes are hydraulically interconnected in a serial configuration via deflection zones at the end faces, so that, in the front and/or rear cover element, the flow is deflected into the respective adjacent heat exchanger tube. Overall, therefore, between the return and supply connection nozzles, a relatively long flow path is formed having relatively high flow velocities.

In a third specific embodiment, the heat exchanger tubes are traversed by the supply and return water flow in alternating sequence on the periphery. In this context, the flow is deflected within the front and/or rear cover element; either from a first heat exchanger tube, which directs cooler return water to an adjacent heat exchanger tube that is conducting warmer supply water, thus, in each case, a U-shaped flow guidance via two tubes having supply and return connection nozzles. Or the flow is directed via a shared deflection chamber from all heat exchanger tubes conducting return water to all heat exchanger tubes conducting supply water.

In a fourth specific embodiment, the heat exchanger tubes are subdivided in each case into at least two flow channels. At least two flow channels are obtained through the use of at least one dividing wall, namely an inner flow channel proximate to the flow channel and at least one larger-diameter, outer flow channel. The at least two flow channels may be hydraulically interconnected within one heat exchanger tube, so that, starting out from a water distribution chamber at the end-face side, the outer, larger-diameter flow channel is first traversed in parallel by the flow of cooler return water in all individual heat exchanger tubes, and, subsequently thereto, the inner flow channel proximate to the combustion chamber is traversed in each case in parallel by the flow of warmer supply water. In the process, a parallel through-flow through all individual heat exchanger tubes arises over the entire circumference.

Alternatively, all flow channels in all heat exchanger tubes may be hydraulically interconnected in a serial configuration via deflection zones at the end faces, thereby resulting in an interlinking of all flow channels. In a first variant, when heat exchanger tubes having at least two flow channels are used, all outer flow channels, which are distant from the combustion chamber, and, in each case, all inner flow channels, which are proximate to the combustion chamber, are serially connected. It is thus achieved that, starting out from a return connection nozzle in a cover element, all outer flow channels are first annularly traversed by flow and, subsequently thereto, all inner flow channels are annularly traversed by flow, in succession.

Only one single overflow site in one cover element is then required between the resulting inner and outer water rings. Apart from that, within the cover elements, the flow is only redirected in this case from one heat exchanger tube into the next adjacent one on the same circumference. In a second variant for heat exchanger tubes having at least two flow channels, the flow emerges at one end face from an outer flow channel, which is distant from the combustion chamber, of a first heat exchanger tube and enters into the inner flow channel, which is proximate to the combustion chamber, of the next adjacent heat exchanger tube, respectively. At the respective other end face, the flow emerges from the inner flow channel of this heat exchanger tube and flows over into the outer flow channel of the same heat exchanger tube.

In a heat exchanger tube, the inner flow channel that is proximate to the combustion chamber advantageously has a smaller cross section than the outer flow channel that is distant from the combustion chamber. Also, the inner flow channel, which is proximate to the combustion chamber, in a heat exchanger tube may be dimensioned in such a way that higher flow velocities arise than in the outer flow channel which is distant from the combustion chamber. The geometry of the gap for allowing the passage of heating gases between the heat transfer surfaces bounding the gap is able to be influenced by the deformation process during manufacture of a heat exchanger tube. Thus, it is readily possible to adapt the gap width in the radial direction to the heating gas volume that is reduced in response to the cooling, or to provide the heat transfer surfaces with turbulence-enhancing means.

In addition, one or two adjacent, mutually opposing surfaces delimiting the gap may be provided with projections that define the gap width and that are braced against each other and/or against the opposing surface. By employing the configuration in accordance with the exemplary embodiments and/or exemplary methods of the present invention, a heat exchanger for a heating device is obtained that is very well suited for a condensing operation, and that features very compact dimensions and excellent heat transfer properties. All of the water-side connections are located on one side where they are readily accessible. The temperature distribution in the heat exchanger is optimized by the manner in which the flow channels are subdivided, and the effectiveness is enhanced over known principles, in particular those involving tubular coils. A vertical configuration of the separating wall within a heat exchanger tube, thus in the radial direction, is also possible. Besides facilitating a simple production, the overall configuration employing substantially identical heat exchanger tubes also provides the advantage of variably covering different lengths for different firing and heat exchanger capacities. Nevertheless, all attachment parts mounted on the end-face side, as well as the connection between the cover elements and the water-conducting heat exchanger tubes then remain the same. Only the surrounding shell varies in length. Due to the low exhaust gas temperatures, this may even be manufactured of plastic.

When an extruded section of aluminum is selected, many diverse configuration options present themselves in the manufacturing of heat exchanger tubes. It is even possible for stainless steel to be used, particularly when it is a question of a tube having one single chamber. Welding, soldering and adhesive bonding are suited as joining methods for heat exchanger tubes, cover elements, and/or water-conducting parts.

An exemplary embodiment of the present invention is illustrated in the drawing. It shows a heat exchanger of a heating device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective overall view including a sectional view in the corner region.

FIG. 2 shows individual parts in an exploded view.

DETAILED DESCRIPTION

A cylindrical combustion chamber 1 is radially bounded by a heat exchanger which has at least one gap 2 for the passage of heating gases. A front cover element 3 for accommodating a burner (not shown) and a rear cover element 4 are used as a closure for combustion chamber 1. An exhaust-gas collection chamber 5 is located underneath a surrounding shell (not shown) having a connection nozzle for an exhaust gas line radially outside of the heat exchanger. The heat exchanger is composed of a plurality of annularly configured heat exchanger tubes 6 having a trapezoidal cross section that are disposed in parallel to the longitudinal axis of combustion chamber 1 and that, between them, form an axially extending gap 2 for the passage of the heating gases in the radial direction.

Heat exchanger tubes 6 are each subdivided by a separating wall 7 into an inner flow channel 8, which is proximate to the combustion chamber, and an outer, larger-diameter flow channel 9. In this context, all flow channels 8, 9 in all heat exchanger tubes 6 are hydraulically interconnected in a serial configuration via deflection zones 10 at the end faces, thereby providing an interlinking of all flow channels 8, 9 between the return and supply connection nozzles.

To form deflection zones 10, other annular covers 11 are mounted on cover elements 3, and integrally formed thereon are mounts 12 for the heat exchanger tubes that engage internally into the same, thereby centering them at the end-face side and providing for a readily sealable overlapping surface in the connection region. In addition, a circumferential, inwardly facing groove 13 for receiving the cylindrical shell surrounding exhaust-gas collection chamber 5, is located in each case in the outer region of cover elements 3, 4. 

1-16. (canceled)
 17. A condensing heating device, comprising: one of a gas burner and an oil burner in a cylindrical combustion chamber that is radially bounded by a heat exchanger, wherein there is at least one gap for a passage of heating gases through the heat exchanger into an exhaust-gas collection chamber which is configured radially outside of the heat exchanger and which has a surrounding shell having a connection nozzle for an exhaust gas line; a front cover element for accommodating the burner; a rear cover element as a closure for the combustion chamber; supply connection nozzles; and return connection nozzles; wherein the heat exchanger includes a plurality of annularly configured heat exchanger tubes that are disposed in parallel to a longitudinal axis of the combustion chamber and that form an axially extending gap in each case between two adjacent heat exchanger tubes for the passage of the heating gases in the radial direction.
 18. The heating device of claim 17, wherein a cross section of the heat exchanger tubes is one of round, oval, and flattened to enlarge a length of the gap in the radial direction.
 19. The heating device of claim 17, wherein the heat exchanger tubes have at least one of a box-shaped cross section and a trapezoidal cross section.
 20. The heating device of claim 17, wherein the heat exchanger tubes are traversed by flow on the water side, in parallel, from one end face to the other, and wherein the return connection nozzle is installed in the one cover element and the supply connection nozzle is in the other.
 21. The heating device of claim 17, wherein all of the heat exchanger tubes are hydraulically interconnected in a serial configuration via deflection zones at the end faces, so that in at least one of the front cover element and the rear cover element, the flow is deflected into the respective adjacent heat exchanger tube.
 22. The heating device of claim 17, wherein the heat exchanger tubes are traversed by the supply and return water flow in alternating sequence on the periphery, and the flow is deflected within at least one of the front cover element and the rear cover element, either from a first heat exchanger tube that conducts return water, to an adjacent heat exchanger tube that conducts supply water, or via a shared deflection chamber from all heat exchanger tubes that conduct return water to all heat exchanger tubes that conduct supply water.
 23. The heating device of claim 17, wherein the heat exchanger tubes are subdivided in each case into at least two flow channels.
 24. The heating device of claim 23, wherein the at least two flow channels are subdivided by at least one dividing wall into an inner flow channel, which is proximate to the combustion chamber, and at least one outer, larger-diameter flow channel.
 25. The heating device of claim 17, wherein the at least two flow channels are hydraulically interconnected within one heat exchanger tube, so that starting out from a water distribution chamber at the end-face side, the outer, larger-diameter flow channel is first traversed by the flow of cooler return water in parallel in all individual heat exchanger tubes, and subsequently thereto, the inner flow channel, which is proximate to the combustion chamber, is traversed in parallel by the flow of warmer supply water.
 26. The heating device of claim 17, wherein all of the flow channels in all heat exchanger tubes are hydraulically interconnected in a serial configuration via deflection zones at the end faces and resulting in an interlinking of all flow channels.
 27. The heating device of claim 17, wherein when heat exchanger tubes having at least two flow channels are used, in each case, all outer flow channels, which are distant from the combustion chamber, and all inner flow channels, which are proximate to the combustion chamber, are serially connected, so that starting out from the return connection nozzle in a cover element, first all outer flow channels and subsequently thereto, all inner flow channels are traversed by flow.
 28. The heating device of claim 17, wherein when heat exchanger tubes having at least two flow channels are used, the flow emerges at one end face in each case from an outer flow channel, which is distant from the combustion chamber, of a first heat exchanger tube and enters into the inner flow channel, which is proximate to the combustion chamber, of the next adjacent heat exchanger tube, and the flow at the other end face emerges in each case from the inner flow channel of this heat exchanger tube and flows over into the outer flow channel of the same heat exchanger tube.
 29. The heating device of claim 17, wherein in a heat exchanger tube, the inner flow channel that is proximate to the combustion chamber has a smaller cross section than the outer flow channel that is distant from the combustion chamber.
 30. The heating device of claim 17, wherein the inner flow channel, which is proximate to the combustion chamber, in a heat exchanger tube is dimensioned so that higher flow velocities arise than in the outer flow channel, which is distant from the combustion chamber.
 31. The heating device of claim 17, wherein the geometry of the gap for the passage of heating gases between the heat transfer surfaces bounding the gap is able to be influenced by the deformation process during manufacture of a heat exchanger tube.
 32. The heating device of claim 17, wherein one or two adjacent, mutually opposing surfaces delimiting the gap are provided with projections that define the width of the gap and that are braced against at least one of each other and the opposing surface. 